In recent years, an automatic transmission called a dual-clutch (or twin-clutch) type has been proposed. The dual-clutch type automatic transmission is generally equipped with a drive force transmission path constituted of a clutch installed between two input shafts, which are connected to a prime mover output shaft, so as to connect/disconnect either of the input shafts to/from the prime mover output shaft and a gear selecting mechanism that can connect one of a plurality of speed gears, which are installed between the two input shafts and two output shafts, to one of the two output shafts. One example of this is a technique stated in the Patent Reference 1 below.
As stated in the Patent Reference 1, in the dual-clutch type automatic transmission, since a gear corresponding to a desired speed is connected to the relevant output shaft through the gear selecting mechanism and clutch, the gear selecting mechanism of the drive force transmission path associated with the desired speed is operated beforehand prior to the clutch engagement (so-called pre-shift operation is conducted) in order to improve the response of shifting.